From nobody Mon Feb 9 00:46:39 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3B9A6C77B73 for ; Tue, 23 May 2023 03:23:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232946AbjEWDXW (ORCPT ); Mon, 22 May 2023 23:23:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40580 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233597AbjEWDXL (ORCPT ); Mon, 22 May 2023 23:23:11 -0400 Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 6F72618E for ; Mon, 22 May 2023 20:23:07 -0700 (PDT) Received: from loongson.cn (unknown [113.200.148.30]) by gateway (Coremail) with SMTP id _____8Ax3eqaMWxknCcLAA--.19119S3; Tue, 23 May 2023 11:23:06 +0800 (CST) Received: from linux.localdomain (unknown [113.200.148.30]) by localhost.localdomain (Coremail) with SMTP id AQAAf8BxFLGZMWxk3ttvAA--.56063S2; Tue, 23 May 2023 11:23:05 +0800 (CST) From: Tiezhu Yang To: Huacai Chen , WANG Xuerui , Christian Brauner , Andy Lutomirski , Thomas Gleixner , Vincenzo Frascino Cc: loongarch@lists.linux.dev, linux-kernel@vger.kernel.org, loongson-kernel@lists.loongnix.cn Subject: [PATCH v2] LoongArch: Add support to clone a time namespace Date: Tue, 23 May 2023 11:23:04 +0800 Message-Id: <1684812184-5849-1-git-send-email-yangtiezhu@loongson.cn> X-Mailer: git-send-email 2.1.0 X-CM-TRANSID: AQAAf8BxFLGZMWxk3ttvAA--.56063S2 X-CM-SenderInfo: p1dqw3xlh2x3gn0dqz5rrqw2lrqou0/ X-Coremail-Antispam: 1Uk129KBjvJXoWxuw4DJrW7KF1kurW7JF48tFb_yoWxWF4fpF WSkrnrtw4Utry8KryUJ3sruwn8Krn7Gw42gF1jgayfAF1I9ryDZr1vyr95AFWYy3ykGryx WaySqr45ZF4DXw7anT9S1TB71UUUUjUqnTZGkaVYY2UrUUUUj1kv1TuYvTs0mT0YCTnIWj qI5I8CrVACY4xI64kE6c02F40Ex7xfYxn0WfASr-VFAUDa7-sFnT9fnUUIcSsGvfJTRUUU bS8YFVCjjxCrM7AC8VAFwI0_Jr0_Gr1l1xkIjI8I6I8E6xAIw20EY4v20xvaj40_Wr0E3s 1l1IIY67AEw4v_Jrv_JF1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xv wVC0I7IYx2IY67AKxVW5JVW7JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwA2z4 x0Y4vEx4A2jsIE14v26r4UJVWxJr1l84ACjcxK6I8E87Iv6xkF7I0E14v26r4UJVWxJr1l n4kS14v26r1Y6r17M2AIxVAIcxkEcVAq07x20xvEncxIr21l57IF6xkI12xvs2x26I8E6x ACxx1l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r126r1DMcIj6I8E 87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lc7CjxV Aaw2AFwI0_JF0_Jw1l42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1l4IxY O2xFxVAFwI0_Jrv_JF1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGV WUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_ Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r1j6r4UMIIF0xvE42xK8VAvwI8IcIk0rV WUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r1j6r4U YxBIdaVFxhVjvjDU0xZFpf9x07jOiSdUUUUU= Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" When execute the following command to test clone3 on LoongArch: # cd tools/testing/selftests/clone3 && make && ./clone3 we can see the following error info: # [5719] Trying clone3() with flags 0x80 (size 0) # Invalid argument - Failed to create new process # [5719] clone3() with flags says: -22 expected 0 not ok 18 [5719] Result (-22) is different than expected (0) This is because if CONFIG_TIME_NS is not set, but the flag CLONE_NEWTIME (0x80) is used to clone a time namespace, it will return -EINVAL in copy_time_ns(). Here is the related code in include/linux/time_namespace.h: #ifdef CONFIG_TIME_NS ... struct time_namespace *copy_time_ns(unsigned long flags, struct user_namespace *user_ns, struct time_namespace *old_ns); ... #else ... static inline struct time_namespace *copy_time_ns(unsigned long flags, struct user_namespace *user_ns, struct time_namespace *old_ns) { if (flags & CLONE_NEWTIME) return ERR_PTR(-EINVAL); return old_ns; } ... #endif Here is the complete call stack: clone3() kernel_clone() copy_process() copy_namespaces() create_new_namespaces() copy_time_ns() clone_time_ns() Because CONFIG_TIME_NS depends on GENERIC_VDSO_TIME_NS, select GENERIC_VDSO_TIME_NS to enable CONFIG_TIME_NS to build the real implementation of copy_time_ns() in kernel/time/namespace.c. Additionally, it needs to define some arch dependent functions such as __arch_get_timens_vdso_data(), arch_get_vdso_data() and vdso_join_timens(), then the failed test can be fixed. At the same time, modify the layout of vvar to expand a page size for timens_data, and also map it to zero pfn before creating time namespace. Signed-off-by: Tiezhu Yang --- arch/loongarch/Kconfig | 1 + arch/loongarch/include/asm/vdso/gettimeofday.h | 7 +++ arch/loongarch/kernel/vdso.c | 63 ++++++++++++++++++++++= +--- 3 files changed, 65 insertions(+), 6 deletions(-) diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig index d38b066..93b167f 100644 --- a/arch/loongarch/Kconfig +++ b/arch/loongarch/Kconfig @@ -80,6 +80,7 @@ config LOONGARCH select GENERIC_SCHED_CLOCK select GENERIC_SMP_IDLE_THREAD select GENERIC_TIME_VSYSCALL + select GENERIC_VDSO_TIME_NS select GPIOLIB select HAS_IOPORT select HAVE_ARCH_AUDITSYSCALL diff --git a/arch/loongarch/include/asm/vdso/gettimeofday.h b/arch/loongarc= h/include/asm/vdso/gettimeofday.h index 7b2cd37..1af88ac 100644 --- a/arch/loongarch/include/asm/vdso/gettimeofday.h +++ b/arch/loongarch/include/asm/vdso/gettimeofday.h @@ -94,6 +94,13 @@ static __always_inline const struct vdso_data *__arch_ge= t_vdso_data(void) return get_vdso_data(); } =20 +#ifdef CONFIG_TIME_NS +static __always_inline +const struct vdso_data *__arch_get_timens_vdso_data(const struct vdso_data= *vd) +{ + return get_vdso_data() + PAGE_SIZE; +} +#endif #endif /* !__ASSEMBLY__ */ =20 #endif /* __ASM_VDSO_GETTIMEOFDAY_H */ diff --git a/arch/loongarch/kernel/vdso.c b/arch/loongarch/kernel/vdso.c index eaebd2e..5bb2b4f 100644 --- a/arch/loongarch/kernel/vdso.c +++ b/arch/loongarch/kernel/vdso.c @@ -14,6 +14,7 @@ #include #include #include +#include #include =20 #include @@ -22,7 +23,22 @@ #include #include =20 +/* + * The layout of vvar: + * + * high + * +----------------+----------------+ + * | timens_data | PAGE_SIZE | + * +----------------+----------------+ + * | vdso_data | | + * | vdso_pcpu_data | VDSO_DATA_SIZE | + * +----------------+----------------+ + * low + */ +#define VVAR_SIZE (VDSO_DATA_SIZE + PAGE_SIZE) + extern char vdso_start[], vdso_end[]; +extern unsigned long zero_pfn; =20 /* Kernel-provided data used by the VDSO. */ static union { @@ -73,6 +89,37 @@ static int __init init_vdso(void) } subsys_initcall(init_vdso); =20 +#ifdef CONFIG_TIME_NS +struct vdso_data *arch_get_vdso_data(void *vvar_page) +{ + return (struct vdso_data *)(vvar_page); +} + +/* + * The vvar mapping contains data for a specific time namespace, so when a + * task changes namespace we must unmap its vvar data for the old namespac= e. + * Subsequent faults will map in data for the new namespace. + * + * For more details see timens_setup_vdso_data(). + */ +int vdso_join_timens(struct task_struct *task, struct time_namespace *ns) +{ + struct mm_struct *mm =3D task->mm; + struct vm_area_struct *vma; + + VMA_ITERATOR(vmi, mm, 0); + + mmap_read_lock(mm); + for_each_vma(vmi, vma) { + if (vma_is_special_mapping(vma, &vdso_info.data_mapping)) + zap_vma_pages(vma); + } + mmap_read_unlock(mm); + + return 0; +} +#endif + static unsigned long vdso_base(void) { unsigned long base =3D STACK_TOP; @@ -88,7 +135,7 @@ static unsigned long vdso_base(void) int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) { int ret; - unsigned long vvar_size, size, data_addr, vdso_addr; + unsigned long size, data_addr, vdso_addr; struct mm_struct *mm =3D current->mm; struct vm_area_struct *vma; struct loongarch_vdso_info *info =3D current->thread.vdso; @@ -100,17 +147,16 @@ int arch_setup_additional_pages(struct linux_binprm *= bprm, int uses_interp) * Determine total area size. This includes the VDSO data itself * and the data pages. */ - vvar_size =3D VDSO_DATA_SIZE; - size =3D vvar_size + info->size; + size =3D VVAR_SIZE + info->size; =20 data_addr =3D get_unmapped_area(NULL, vdso_base(), size, 0, 0); if (IS_ERR_VALUE(data_addr)) { ret =3D data_addr; goto out; } - vdso_addr =3D data_addr + VDSO_DATA_SIZE; + vdso_addr =3D data_addr + VVAR_SIZE; =20 - vma =3D _install_special_mapping(mm, data_addr, vvar_size, + vma =3D _install_special_mapping(mm, data_addr, VVAR_SIZE, VM_READ | VM_MAYREAD, &info->data_mapping); if (IS_ERR(vma)) { @@ -121,7 +167,12 @@ int arch_setup_additional_pages(struct linux_binprm *b= prm, int uses_interp) /* Map VDSO data page. */ ret =3D remap_pfn_range(vma, data_addr, virt_to_phys(&loongarch_vdso_data) >> PAGE_SHIFT, - vvar_size, PAGE_READONLY); + VDSO_DATA_SIZE, PAGE_READONLY); + if (ret) + goto out; + + ret =3D remap_pfn_range(vma, data_addr + VDSO_DATA_SIZE, zero_pfn, + PAGE_SIZE, PAGE_READONLY); if (ret) goto out; =20 --=20 2.1.0